Tuning device for radio receivers or the like



March 1939- W. H. GRIMDITCH ET AL 2,151,595

TUNING DEVICE FOR RADIO RECEIVERS OR THE LIKE Filed April 25, 1957 4 sheets-sheet March 21, 1939. w H. GRIMDITCH ET AL TUNING DEVICE FOR RAD-IO RECEIVERS OR THE LIKE 4 Sheets-Sheet '2 Filed April 23 1937 A a y GU March 21, 1939. w. H. GRIMDITCH E1. AL

TUNING DEVICE FOR RADIO RECEIVERS OR THE LIKE Filed April 25, 1937 4 Sheets-Sheet 3 (Ill/ll March 21, 193. -W. H. GREMDITCH ET AL 9 TUNING DEVICE FOR RADIO RECEIVERS OR THE LIKE Filed April 25, 1 9 57 4 Sheets-Sheet 4 able adjustment of the said elements along the Patented Mar. 21, 1939 UNITED STATES PATENT OFFICE TUNING DEVICE FOR RADIO RECEIVERS OR THE LIKE Application April 23, 1937, Serial No. 138,642

17 Claims. (01. 250-20) This invention relates to tuning devices for member controls switching means for rendering radio receivers or the like and, more particularly, the radio receiver operative or inoperative deto a novel tuning device which is simple in conpending upon the particular axial position of the struction and economic to manufacture and assaid member. In one of the axial positions of semble, and which embodies the several novel said member, the switching'means renders the features described hereinafter. radio receiver operative so that the tuning ad- One object of the invention is to provide anovel justment may be made by ear. In the other radio tuning device by means of which a radio positions of the said member and while the memreceiver may be tuned readily to a desired her is being manipulated to tune the radio rebroadcasting station by the simple process of Ver rap y by means of the stop elements as moving a rotatable member into cooperative reabove mentioned, the Switching means renders lation with a selected one of a plurality of stop the radio receiver inoperative until the desired elements, to thereby adjust the tuning element on is P p y tuned The device is S0 or elements of the receiver rapidly and easily to tedt at if a desired station is not D D- a position corresponding to the position of the y tu d t switching means maintains the selected stop element, whereby the radio receiver radio receiver p v is tuned to a particular station represented by A further Object of the invention is to p v de the said top element. M r ifi ll th d a Vernier knob carried by the said member and vice comprises a stationary support carrying a pte to frie io ally en age a stationary ennuplurality of selectable elements which are anlar frictional surface to permit fine adjustment nu1ar1y arranged d adapted t b selectively by rotating the said Vernier knob about its axis. engaged by a, rotatable member to thus adjust or Other objects and featuresof the invention Will position the tuning element or elements of the be apparent hereinafter- In t accompa y radio receiver. The rotatable member carries an drawings: axially movable member which is maintained in 1 is front w Of the tuning v e one of three positions. In one of these positions, mounted in a radio cabinet; it is interlocked with one of the several stops. 2 is a bottom P w Of the same;

Another object of the invention is to provide a 3 s a sectional V w of th an s ptuning device in which the tuning knob mov arated from the cabinet, taken along line 33 of annularly around the tuning dial, and in which showing the axially movable member in the dial mechanism is located behind the face cooperative engagement W a Selected Stop ole- 0f the dial but can be easily and quickly adjusted ment; fr th from; of th bi t Fig. 4 is an enlarged sectional view taken sti11 th b t of t invention is t pro through the axially movable member as disclosed vide a device of the character above mentioned in 3 and showing the e ents associated wherein the said selectable elements are indiwith said e vidually adjustable in a simple manner from the 4A is a sectional V ew Of an adj st ng tool; front of the radio cabinet to cause the said ele- 4B is an end w of the tool; m-ents to correspond respectively to different Fig. 5 is a fragmentary sectional w s owing broadcasting stations. More particularly, the the axially movable member in another 0 ts said selectable elements are mounted on an annu- Positions; lar track and are so constructedthat they may 6 is a similar V ew shOWing the axially be loosened or tightened by means of a tool inmovable member in Still another position; serted from the front of the radio cabinet to enswitch circuit and showing the connection thereof to a radio receiver;

Fig. 8 is a face view of the stationary supporting member carrying the stop elements; and

Fig. 9 is a fragmentary sectional view taken along line 9-9 of Fig. 3.

Referring particularly to Figs. 1 to 3, there is provided a supporting member or plate I which is adapted to be mounted on a radio chassis within a radio cabinet in proper relation to the front panel la of the cabinet. The plate I carries a said track.

A further-object of the invention is to provide a device of the stated character wherein the above-mentioned axially movable member is provided with an axial opening through which a tool may be inserted to loosen or tighten the stop elements as above mentioned.

A further object of the invention is to provide a radio tuning device of the stated character wherein the above-mentioned axially movable Fig. 7 is. a diagrammatic illustration of the plurality of annularly arranged stop elements 2, the construction and purpose of which will be described in detail later. A rotatable shaft 3 extends through plate I as shown in Fig. 3 and is supported by a bearing block 4 attached to the plate I. The shaft 3 is connected to the tuning elements or condensers of the radio receiver or I to suitable driving means therefor, preferably by means of a flexible coupling 5. It will be understood, therefore, that rotation of shaft 3 serves to actuate the tuning element or elements of the radio receiver to tune the receiver to a desired station.

The block 4 carries a housing 6 within which there is mounted a stationary translucent dial I having graduations and indicia thereon as shown in Fig. 1, indicating the frequency to which the set may be tuned and the location of some of the various broadcasting stations on the dial. On the end of shaft 3, there is provided a pointer 8 which moves with the shaft adjacent the face of the dial. A transparent cover or face plate 9 is secured to the housing 6 by means of a mounting ring In which has a front annular serrated or beaded surface II, the purpose of which will be described later. One or more light sources I2 are mounted within the housing to eliminate the translucent dial 1.

A crank arm I3 is attached to the rotatable shaft 3 so that the shaft may be rotated by rotating the crank arm. At its outer end, the arm I3 has an angularly extending arm portion I4 which carries a hollow support or boss I5, as shown more clearly in Figs. 4 to 6. A tubular or hollow member I 5, which will be described in detail later, is slidably and rotatably carried by the support I and is provided with a knob I! by means of which it may be moved axially or moved bodily to turn the crank arm I3 and thus rotate shaft 3. The member I6 has three axial positions, viz., an outer position, an intermediate position, and an inner position. The manner in which the device functions when member I6 is positioned in each of its three positions will be clearly understood later.

Referring now to Fig. 8, the supporting plate I is provided with an annular track I9 which is formed by two concentric flanged rings 20 and 2I having the cross-sectional shape shown in Fig. 4. Each of the stop elements 2 has a conical head 22 and a threaded shank 23 adapted to extend between the rails of track I9. A nut 24, which seats snugly between the railmembers, serves to hold the stop element in place on the track. The rails of the track are cut away, as shown at 25 in Fig. 8, in order thatthe stop elements with the nuts attached thereto may be inserted and moved into place on the track. The recess 25 is of such size and shape. that it permits the nut 24 to be inserted and thenmoved behind the flanges of rails 20 and 2!. The nut 24 may be squared and the recess 25 may like- Wise be square as shown. Since the nut of each stop element is held against rotation by the track rails, the stop elements may be loosened or tightened by turning their conical heads, and in this manner the stop elements may be adjusted to different positions along the annular track. To enable adjustment of the stop elements in this manner from the front of the device, the conical head of each stop element is provided with two opposed recesses 26 which are adapted to receive the forked end of a special tool provided for the purpose of adjustment. A tool comprising a rod having its end cut out to provide two male members adapted to interlock with the recesses 26 in any one of the stop elements may be used to loosen or tighten the stop elements to permit adjustment thereof. Such a simple tool is shown in Figs. 4A and 4B.

The inner end of the axially movable member I6 has an internal conical surface 2'! (see Fig. 6) which is adapted to fit over and snugly engage the conical head of any one of the stop elements. When the member I6 is moved to its inner position above mentioned, it may engage the head of a selected stop element in the manner shown in Fig. 4. The member I5 not only serves cooperatively with the conical heads of the stop elements to accurately adjust the tuning element or elements of the radio receiver, but also serves to position the stop elements during adjustment thereof. To this end, the hollow member I6 is adapted to receive the tool above mentioned, the tool being inserted longitudinally through the member I6 and brought into engagement with a selected stop element. When the stop element has been loosened by means of the tool in this manner, the member I 6 may be moved to move the stop element to the desired position as determined by the aural reception of the radio receiver. For example, if it is desired to move one of the stop elements to a position corresponding to a particular station, the member Iii in the axial position shown in Fig. 4 is moved, carrying the stop element with it until the radio receiver is tuned to the particular station. The stop element is then tightened in place on the track I9 by means of the tool as above described. Thereafter, the particular stop element serves cooperatively with the member I6 in the rapid tuning operation of the device.

Adjacent the knob N, there is provided on member I6 a slidable and rotatable disk 28 (see Fig. 4) to which there is secured a small collar or washer 29 formed of frictional material such as leather or rubber. The disk 28, which serves as a Vernier knob as described below, is urged outward against knob H by means of a spring pose of this structure is two fold. As described hereinafter, in the intermediate position of the member I6, fine adjustment of the tuning of the radio receiver by ear may be effected by rotating the disk 28 while holding it inwardly with the collar 29 against the surface II. The frictional engagement between the surface I! and the collar 29 causes the collar 29 to ride along the annular surface II, thus moving the member I5 and rotating crank arm I3. During this method of tuning, the radio receiver is operative so that it may be tuned by ear in the usual manner. In addition to this function, however, the cooperative frictional surfaces enable fine adjustment of any one of the stop elements 2. When one of the stop elements is adjusted in the manner above described, instead of moving the member It by means of its knob H, the adjustment may be made by pressing the disk 28 inwardly and rotating it to cause slow movement of member I 6 by means of the frictional surfaces. There is thus provided a verniertuning'control and adjustment device.

The tuning device is adapted to be mounted in a suitable cabinet having a circular opening in its front face id, as shown in Figs. 1 and 2. The dial housing 6 may extend into the opening so that the face plate 9 is flush with or projects slightly beyond the face of the cabinet. The tuning knob shaft i6, which carries the tuning knob, also extends through the opening in the cabinet which must be large enough to permit this shaft to rotate about the dial housing 6, as described above. To close the opening between the housing and the cabinet face there is provided an annular movable bezel or ring 29w which is carried by the crank arm housing l5, as shown in Figs. 2 and 9. The use of this movable bezel not only improves the appearance of the device but also permits the locating of the stop mechanisms behind the front of the cabinet in a semi-concealed and relatively inaccessib-le position. While means are provided for easy adjustment of the stop mechanism, accidental and injurious contact with them is thus made diflicult. As shown in Fig. 2, a felt ring 2911 may be carried by the bezel 29a to close the small space between the bezel 29a and the stationary bezel 290 on the cabinet, and to exclude light.

In further accordance with the invention, there is provided switching means for rendering the radio receiver operative or inoperative for different axial positions of the member l6. To this end, there is provided on the supporting plate I, an electrically conductive ring 30 which is insulated from the supporting plate by means of the insulating ring 3| (see Figs. 3, 5, 6 and 8). The ring 30 forms one contact of a switch 32, while a spring arm 33 constitutes the other element of this switch. The spring arm 33 carries a contact button 34 which normally engages the ring 3!! by virtue of the resilience of the arm 33. The spring arm 33 is carried by crank arm i3 but is insulated therefrom by means of insulating washers 35. A conductor 33 is connected to ring 3! while a second conductor 31 is: connected to the spring arm 33. The further connection of conductor 36 will be described later. Conductor 37 has its opposite end connected to a contact button 38 (see Fig. 9) which is carried by an insulating plunger 49 slidably disposed in a transverse opening or recess provided in the wall of the hollow structure [5. The plunger 39 is urged toward member l6 by means of a coil spring 43 and the spring-operated plunger assembly is. adjustably held by means of the screw plug 4 I. The contact button 38, together with the member l6, constitutes a switch, as described further hereinafter, which is connected in series relation with the switch 32.

The angular extension 14 of arm i3 is provided with a recess 42 (see Figs. 4 to 6) within which there is carried a transverse pin 43 on which there is mounted a pawl 44 which is adapted to actuate the spring arm 33 to open switch 32. The pawl 44 is provided with an elongated slot 45 within which the pin 43 is slidably disposed. Thus, the pawl is pivotally mounted on pin 43 and is adapted for bodily movement thereon. A spring 46 urges the pawl 44 to inoperative position and normally maintains the pawl in such position, .as shown in Fig. 5. When the member i6 is moved to its inner position, its inner end engages the nose 41 of the pawl and causes pivotal movement of the pawl about the pin 43. If the member I6 is not in cooperative relation with it (member it) moves the nose 4'! of the pawl into engagement with the conical head of the stop element, and the conical surface of the stop element serves as a cam to move the pawl into engagement with the spring arm 33. In other words, the pivotal movement of the pawl caused by member It and the simultaneous cam action of the plunger head on the pawl, together cause the pawl to move to the position shown in Fig. 4, the pin 43 riding to the opposite end of slot 45. This causes the nose 43 of the pawl to engage the end of spring arm 33 and to move the spring arm to the position shown in Fig. 3, thus opening the switch 32. As will be more clearly understood later, the switch 32 determines whether the radio receiver is operative or inoperative when the member [6 is in its inner axial position. It will be noted that the switch is opened only when the member It is moved into cooperative relation with one of the stop elements and, therefore, the receiver is rendered operative only if a desired station is tuned in by means of a selected stop and the member Hi. If, through inadvertence, the member 86 is not aligned with a selected stop element so that the inner end of member I 6 does not properly engage the conical head of the stop element, the switch 32 is not opened and, therefore, the radio receiver is maintained inoperative. It will be seen, therefore, that the person tuning the radio receiver will know at once that he has not located the member [6 in proper relation to the stop element.

The member It comprises two interfitting and interlocked metallic sleeves 49 and 50 which are arranged as clearly illustrated in Fig. 4. An insulating collar is mounted on the sleeve 49 between a flange 52 thereof and the end of sleeve 55. The sleeve 49 is provided with annular recesses 53, 54 and 55 which are selectably engageable by .a spring-pressed plunger 56 (see Fig. 9) to maintain the member 16 in any one of its three positions. The plunger 55, together with its associated spring 51, is held in a transverse opening in the wall of the hollow support I5 by means of an adjustable screw plug 58. In the outer position of member [6, as shown in Fig. 9, the spring-pressed plunger 55 seats in the annular recess 55. As the member i6 is moved inwardly axially, the spring-pressed plunger seats successively in the recesses 54 and 53. Thus, the member 83 is snapped into any one of its three positions and is held in position by the detent mechanism.

When the member 16 is in its outer position, as shown in Fig. 9, the contact button 38 engages the metallic surface of member 15 on the left side of the insulating collar 5! as viewed in the figure. When the member is is moved to its intermediate position, the contact button 38 engages the insulating collar 5|. When the member i3 is moved to its inner position, the contact button 38 engages the metallic surface of member it on the right side of the insulating collar M. In this manner, the axial movement of member It effects a switching action which, together with switch 32, determines whether the radio receiver is operative or inoperative.

Referring now to Fig. '7, there is shown a portion 59 of the audio frequency channel of a conventional radio receiver employing a volume control device 60 in the form of a potentiometer having a movable contact 6|. The conductor 36 which is connected to ring 30 as above mentioned may be connected to the movable arm of the volume control device as illustrated. The metallic portions of member l6, which is shown diagram matically in Fig. 7, are grounded through the metallic parts of the tuning device sincethe deice is mounted on the radio receiver chassis. This grounding of the mtallic portions of member I6 is illustrated diagrammatically in Fig. 7 at 62. It will now be seen from Fig. '7 that the switch 32, together with the switch formed by member IG and the contact button 38, are connected in series in a circuit extending from the volume control device 60 to ground. When both of the switching devices are closed so that the ground circuit is completed, the radio receiver is rendered inoperative. If either of the switching devices is open, however, the ground circuit is open and the radio receiver is rendered operative.

From the above description, it will be seen that when the member I6 is in its outer position, the two switching devices are closed and the radio receiver is rendered inoperative. At this time, the member I6 is free of the stop elements and it may be rotated to bring it in line with any one of the stop elements (as determined by the pointer 8 and the dial indicia) and then pressed to its inner position into engagement with the stop element. If the selected stop element is properly engaged by member IS, the switch 32 is opened as above described, thus opening the ground circuit and rendering the radio receiver operative. As pointed out above, however, if the member I6 is not in proper relation with the stop element, the switch 32 remains closed so that the radio receiver remains inoperative. It will be noted that the inward movement of member IE will cause the contact button 38 to move over the insulating collar 5|, thus opening the ground circuit momentarily but the contact button 38 will immediately move onto the metallic surface of member IE to the right of collar 5|, thus closing the ground circuit. When the member I 6 is moved axially to its intermediate position, the contact button 38 engages the insulating collar 5| as shown in Fig. 7, thus opening the ground circuit and rendering the radio receiver operative. With the member I 6 in this axial position, the radio receiver may be tuned by ear by pressing disk 28 inwardly and rotating the disk to effect fine adjustment as described above.

In order to maintain the rotatable parts in an adjusted position during the fine tuning operation which does not make use of the stop elements, there is provided a counterbalancing weight 63 which counterbalances the weight of arm I3 and the elements carried thereby. While the weight 63 is shown attached to a part of the coupling 5, it will be apparent that it may be applied to any part of the rotatable structure.

It will be apparent that the device is simple in construction so that it may be manufactured and assembled economically and it embodies the several novel features above described. While a preferred form of the device has been illustrated for the purpose of disclosure, it will be understood that the invention is not thus limited but is capable of various modifications within the scope of the appended claims.

We claim:

1. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of annularly arranged selectable elements carried by said supporting means and adapted for annular adjustment relative to one another, each of said selectable elements having a projecting head, a rotatable shaft for rotating a tuning element of said receiver, a crank arm carried by said shaft, and an axially movable member carried by said arm and adapted to selectively engage one of said elements to stop said tuning element at a predetermined position corresponding to the position of the selected element, said member having an axial opening therethrough terminating in a recess for receiving the head of the selected element and permitting insertion of a tool through said opening for adjustment of said elements.

2. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of annularly arranged selectable elements carried by said supporting means and adapted for annular adjustment relative to one another, each of said selectable elements having a projecting conical head, a rotatable shaft for rotating a tuning element of said receiver, a crank arm carried by said shaft, an axially movable member carried by said arm and adapted to selectively engage one of said elements to stop said tuning element at a predetermined position corresponding to the position of the selected element, said member having an axial opening therethrough terminating in a conical recess for receiving the conical head of the selected element and permitting insertion of a tool through said opening for adjustment of said elements, and means for holding said member in engagement with the selected element.

3. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of selectable elements carried by said supporting means, means for adjusting a tuning element of said receiver including a member movable axially to three positions, means actuatable by said member in one of its axial positions for adjusting said tuning element, said member in another of its axial positions adapted to be moved into alignment with a selected one of said elements to adjust said tuning element, said member in its third axial position adapted to engage the selected element, and switching means for rendering said receiver inoperative when said member is in said secondmentioned position, and for rendering said receiver operative when said member is in its other two positions.

4. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of selectable elements carried by said supporting means, means for adjusting a tuning element of said receiver including a member movable axially to three positions, means actuatable by said member in one of its axial positions for adjusting said tuning element, said member in another of its axial positions adapted to be moved into alignment with a selected one of said elements to adjust said tuning element, said member in its third axial position adapted to engage the selected element, and switching means controlled by said member for rendering said receiver inoperative when said member is in said second-mentioned position or when said member is in its said third position but not in proper engagement with a selected element, and for rendering said receiver operative when said member is in said firstmentioned position or when said member is in its said third position in proper engagement with a selected element.

5. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of selectable elements carried by said supporting means, means for adjustinga tuning element of said receiver including a member movable axially to three positions, means actuatable by said member in one of its axial positions for adjusting said tuning element, said member in another of its axial positions adapted to be moved into alignment with a selected one of said elements to adjust said tuning element, said member in its third axial position adapted to engage the selected element, a normally closed switch operable by said member in its said third axial position, and switching means open when said member is in its first-mentioned position and closed when said member is inits other two positions, said switch and said switching means being serially connected and adapted for connection to said receiver torender it inoperative when both said switch and said switching means are closed.

6. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of selectable elements carried by said supporting means, means for adjusting a tuning element of said receiver including a member movable axially to three positions, means actuatable by said member in one of its axial positions for adjusting said tuning element, said member in another of its axial positions adapted to be moved into alignment with a selected one of said elements to adjust said tuning element, said member in its third axial position adapted to engage the selected element, a normally closed switch, a pawl arranged for actuation by said member and adapted to open said switch only when said member is in proper engagement with a selected element, and switching means open when said member is in its firstmentioned position and closed when said member is in its other two positions, said switch and said switching means being serially connected and adapted for connection to said receiver to render it inoperative when both said switch and. said switching means are closed. I

7. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of selectable elements carried by said supporting means, means for adjusting a tuning element of said receiver including a member movable axially to three positions, means actuatable by said member in one of its axial positions for adjusting said tuning element, said member in another of its axial positions adapted to be moved into alignment with a selected one of said elements to adjust said tuning element, said member in its third axial position adapted to engage the selected element, a normally closed switch, a pawl arranged for actuation by said member and a selected element when said member moves into proper engagement with said element, to thus open said switch only when said member is in proper engagement with said element, and switching means open when said member is in its first-mentioned position and closed when said member is in its other two positions, said switch and said switching means being serially connected and adapted for connection to said receiver to render it inoperative when both said switch and said switching means are closed.

8. In a radio receiver, a cabinet having an opening in the front face thereof, a tuning dial structure disposed within said opening, a plurality of stop elements disposed within said cabinet, means including a member extending into said opening and movable therein about said dial structure for tuning said receiver, an axially movable member carried by said first member and adapted to engage a selected one of said stop elements, and a bezel carried by said first member and serving to substantially close the opening around said dial structure.

9. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of selectable elements carried by said supporting means and adapted for adjustment relative to one another, and a manually movable member for actuating a tuning element of said receiver and adapted to selectively engage one of said elements to stop said tuning element at a predetermined position corresponding to the position of the selected element, said member having an opening therethrough for insertion of a tool to adjust said elements, whereby said elements may be disposed inaccessibly normally but may be adjusted by the said tool.

10. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of annularly arranged selectable elements carried by said supporting means and adapted for annular adjustment relative to one another, each of said selectable elements having a projecting head with spaced recesses for receiving a tool, a rotatable shaft for rotating a tuning element of said receiver, a crank arm carried by said shaft, and an axially movable member carried by said arm and adapted to selectively engage one of said elements to stop said tuning element at a predetermined position corresponding to the position of the selected element, said member having an axial opening there through terminating in a recess for receiving the head of the selected element and permitting insertion of said tool through said opening for adjustment of said elements.

11. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of selectable elements carried by said supporting means, amanually rotatable and axially movable member for rotating a tuning element of said receiver and adapted to selectively engage one of said elements to stop said tuning element at a predetermined position corresponding to the position of the selected element, a stationary member having an annular frictional surface, a friction member carried by and movable axially along said first member into engagement with said surface to effect fine tuning adjustment, and means for maintaining said friction member normally out of engagement with said surface.

12. In a tuning device for a radio receiver or the like, stationary supporting means, a plurality of selectable elements carried by said supporting means, a manually rotatable and axially movable member for rotating a tuning element of said receiver and adapted to selectively engage one of said elements to stop said tuning element at a predetermined position corresponding to the position of the selected element, a stationary member having an annular frictional surface, and a friction member carried by and movable axially along said first member into engagement with said surface to effect fine tuning adjustment.

13. In a radio apparatus, a cabinet having an opening in the front face thereof, a tuning dial structure disposed within said opening, a plurality of stop elements disposed within said cabinet behind the front face thereof, a rotatable arm behind said dial structure for actuating a tuning element of the apparatus, an axially movable member carried by said arm and extending outward through said opening adjacent the edge of the dial, for selectively engaging any one of said stop elements, whereby said member may be moved about the dial into alignment with a selected stop element and then moved axially to engage the said element, and a bezel carried by said arm and serving to conceal the space between the dial structure and the edge of the cabinet opening, whereby said stop elements, said arm and the rear portion of said member are at all times concealed from view.

14. In a radio apparatus, a cabinet having an opening in the front face thereof, a tuning dial structure disposed within said opening, a plurality of stop elements disposed within said cabinet behind the front face thereof, a rotatable arm behind said dial structure for actuating a tuning element of the apparatus, an axially movable member carried by said arm and extending outward through said opening adjacent the edge of the dial, for selectively engaging any one of said stop elements, whereby said member may be moved about the dial into alignment with a selected stop element and then moved axially to engage the said element, a bezel carried by said arm and serving to conceal the space between the dial structure and the edge of the cabinet opening, whereby said stop elements, said arm and the rear portion of said member are at all times concealed from view, a stationary member having an annular frictional surface adjacent said bezel, and a friction member carried by and movable axially along said first member into engagement with said surface to effect fine tuning adjustment.

15. In a radio apparatus, a cabinet having an opening in the front face thereof, a tuning dial structure disposed within said opening, a plurality of adjustable stop elements disposed within said cabinet behind the front face thereof, a rotatable arm behind said dial structure for actuating a tuning element of the apparatus, an axially movable member carried by said arm and extending outward through said opening adjacent the edge of the dial, for selectively engaging any one of said stop elements, whereby said member may be moved about the dial into alignment with a selected stop element and then moved axially to engage the said element, a bezel carried by said arm and serving to conceal the space between the dial structure and the edge of the cabinet opening, whereby said stop elements, said arm and the rear portion of said member are at all times concealed from view, said member having an axial opening therethrough for insertion of a tool to adjust said stop elements, a stationary member having an annular frictional surface adjacent said bezel, and a friction member carried by and movable axially along said first member into engagement with said surafce to effect fine tuning adjustment.

16. In a tuning device for a radio receiver or the like, a plurality of selectable elements, a member constructed and arranged for rotation and for movement in a direction substantially perpendicular to the plane of rotation to selectively engage one of said elements to thereby effect tuning adjustment, a stationary member having an annular frictional surface, and a friction member carried by said first member and movable therealong in said direction into engagement with said surface. to effect fine tuning adjustment.

17. In a tuning device for a radio receiver or WILLIAM H. GRIMDITCH. JOHN M. BOWMAN. LEO B. GLASER. 

